Blade CX Balance problem

[Dick]

Been flying for few months and occasionally need to replace a rotor blade
<G>. With the yellow training balls, things don't get to far out of hand
yet.

After last crash and new blade, a vibration occurs upon liftoff at about 12"
off the ground as speed revs up and quickly becomes a violent shake. I
immediately shut down.

In previous repairs, I had straighten the flybar to eliminate vibration.
This time the flybar appears perfect..

Don't know if it is pertinent or not, but in past I noticed that sometimes
switching the flybar linkage to the other side of the upper rotor blades
smoothed things out.

This rookie would appreciate any help.
Thanks, Dick

[Harry Spillett]

Have you tried checking the mast and feathering spindle?

The easiest way to check them is to roll them over a sheet of glass or a
mirror. a small imperfection can cause a big wobble!

H

"Dick" <rwripper@verizon.net> wrote in message
news:braWf.15973$W75.12710@trnddc07...
> Been flying for few months and occasionally need to replace a rotor blade
> <G>. With the yellow training balls, things don't get to far out of hand
> yet.
>
> After last crash and new blade, a vibration occurs upon liftoff at about
> 12" off the ground as speed revs up and quickly becomes a violent shake. I
> immediately shut down.
>
> In previous repairs, I had straighten the flybar to eliminate vibration.
> This time the flybar appears perfect..
>
> Don't know if it is pertinent or not, but in past I noticed that sometimes
> switching the flybar linkage to the other side of the upper rotor blades
> smoothed things out.
>
> This rookie would appreciate any help.
> Thanks, Dick
>

[The OTHER Kevin in San Diego]

On Tue, 28 Mar 2006 12:59:51 GMT, "Dick" <rwripper@verizon.net> wrote:

>Been flying for few months and occasionally need to replace a rotor blade
><G>. With the yellow training balls, things don't get to far out of hand
>yet.
>
>After last crash and new blade, a vibration occurs upon liftoff at about 12"
>off the ground as speed revs up and quickly becomes a violent shake. I
>immediately shut down.

Check your main shaft to see if it's tweaked. Remove it and roll it
across a piece of glass or a mirror. If it's tweaked, it'll "tick" as
it rolls. You can also check it out with your Mark One Eyeball by
SLOWLY spooling the blades and checking the screw that holds the head
on. If it "wobbles", the shaft is definitely bent.

[Steve]

> Don't know if it is pertinent or not, but in past I noticed that sometimes
> switching the flybar linkage to the other side of the upper rotor blades
> smoothed things out.

I flew a friend's CX last night and was wondering what exactly this
flybar does and how it works. I can see how it changes the pitch of
the top rotor blades, but I'm not sure what would cause the flybar to
move/tilt in the first place. Does it basically act as a damper?

Also, how much harder is the CP to fly than the CX? I was able to
keep the CX hovering in about a 3 foot cube by the end of the first
battery, and smoothed it out a bit from there on the second. Just
barely played with slow forward flight before we called it quits (need
to get a second battery!).

Any opinions on the optional heat sinks for the motors? Anything
else I should consider?

Thanks,
Steve

[The OTHER Kevin in San Diego]

On 29 Mar 2006 00:07:15 -0800, "Steve" <scasko@aol.com> wrote:


> Also, how much harder is the CP to fly than the CX? I was able to
>keep the CX hovering in about a 3 foot cube by the end of the first
>battery, and smoothed it out a bit from there on the second. Just
>barely played with slow forward flight before we called it quits (need
>to get a second battery!).

I've only got about a half battery flight in on the CX and found it
much easier to fly than the CP. Could just be me but the owner of the
LHS regularly flies a CX off his palm in the shop for demos and always
takes the CP out into the parking lot to demo it.

> Any opinions on the optional heat sinks for the motors? Anything
>else I should consider?

Like chicken soup when you have a cold, it couldn't hurt. I put 'em
on my CP the day I got it...

[snowdragon]

we have found some blades weigh a half gram or so different than others
change the blades again or weigh them

[The OTHER Kevin in San Diego]

On Sun, 14 May 2006 00:53:54 GMT, "snowdragon" <iamnot@home.com>
wrote:

>we have found some blades weigh a half gram or so different than others
>change the blades again or weigh them

So balance them.